The sirens of two fire engines have a frequency of 600 Hz each . A man hears the sirens from two engines, one approaching him with a velocity of `36km//h` and the other going away from him at a speed of `54km//h`. What is the difference in frequencies of sound heard ? Take velocity of sound in air `=340m//s`.

The sirens of two ambulances have a frequency of 500 Hz each. An observer hears the sirem from the two engines, one approaching him with a speed of 18 km/hr and other going away from him at a speed of 36 km/hr. Determine the difference in frequency of two sirens heard by the observer. Take, speed of sound in air = 340 m/s.

An engine blowing a whistle of frequency 133 Hz moves with a velocity of 60(m)/(s) towards a hiss from which an echo is heard. Calculate the frequency of the echo heard by the driver. (velocity of sound in air in 340(m)/(s) .)

A siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s. Frequency of the sound to be heard by the listener is ( Take velocity of sound as 300 m/s )

A siren emiting sound of frequency 800Hz is going away from a static listence with a speed of 30 m//s frequency of sound to be beand by the listener is ("velocity of sound" = 330 m//s)

Two aeroplanes A and B ,each moving with a speed of 720 km/hr. are moving directly away from each other.Aeroplane A emits a whistle of frequency 1080 Hz.The apparent frequency heard by a person in plane B will be (velocity of sound in air =340 m/s )

A train in approaching a station with a uniform velocity of 72kmph and the frequency of the whistle of that train is 480Hz . The apparent increase in the frequency of that whistle heard by a stationary observer on the platform is (Velocity of sound in air is 340m//s )

A siren emitting a sound of frequency 2000 Hz moves away from you towards a cliff at a speed of 8 m/s. (a) What is the frequency of the sound you hear coming directly from the siren. (b) What is the frequency of sound you hear reflected off the cliff. Speed of sound in air is 330(m)/(s) .

Two cars are approaching each other at an equal speed of 7.2 km/hr. When they see each other, both blow horns having frequency of 676 Hz. The beat frequency heard by each driver will be _____ Hz. [Velocity of sound in air is 340 m/s.]

One train is approaching an observer at rest and another train is receding from him with the same velocity 4 m//s . Both trains blow whistles of same frequency of 243 H_(Z) . The beat frequency in H_(Z) as heard by observer is (speed of sound in air = 320 m//s )